In a 10-pole 9-slot permanent magnet synchronous motor having coils wound in concentrated winding, three adjacent teeth around which coils of the same phase are wound adjacent to each other, form one teeth group, and three teeth groups are arranged on a yoke. In the conventional synchronous motor described in Patent Literature 1, from among three adjacent teeth around which coils of the same phase are wound, the width of a rotor facing portion of the middle tooth is set wider than respective rotor facing portions of the two teeth on opposite sides to achieve higher efficiency and higher output.